One of the traditionally known mechanical seals used in applications where the temperature of sealed liquid exceeds 200° C. and flushing with coolant is not performed, is a mechanical seal of high-temperature bellows seal type like the one shown in FIG. 10 (hereinafter referred to as “prior art; refer to Patent Literature 1, for example).
The mechanical seal of high-temperature bellows seal type according to the prior art as shown in FIG. 10 is a mechanical seal installed on a shaft seal part 53 formed between a rotational shaft 50 and housing 51 to seal a space between the rotational shaft 50 and housing 51; wherein such mechanical seal has: a collar 54 installed on the housing 51 side; a bellows 55 connected to the collar 54; a retainer 56 connected to the bellows 55; a seal ring 57 engaged with the retainer 56; a mating ring 58 installed on the rotational shaft 50 side; and a cylindrical baffle sleeve 59 provided at a specific interval on the inner periphery side of the collar 54. In addition, steam quench is supplied from a supply hole 64 provided in a seal cover 60, which then flows through the space formed between the inner periphery of the stationary side of the mechanical seal and the outer periphery of the baffle sleeve 59 and reaches the end face of the seal to cool the mechanical seal part, and which also cleans and discharges the liquid seeping from the end face of the seal.
Then, the sliding torque on the end face of the seal ring 57 is transmitted to the retainer 56, bellows 55, and collar 54, in this order, being received by the collar 54 fixed on the seal cover 60 with bolts 63. Minute vibration (stick-slip) occurring in the circumferential direction as a result of change in the lubrication condition of the end face of the seal ring 57 propagates to the retainer 56 and to the bellows 55. To suppress such minute vibration in the circumferential direction, the baffle sleeve 59 fixed on the seal cover 60 with bolts 63 extends to the inner periphery part of the retainer 56 to limit the outer diameter of the baffle sleeve 59 and innermost diameter of the retainer to a minimum gap at some parts (four equidistance points in many cases) along the circumference, while a damper 61 that contacts the inner periphery surface of the bellows 55 to exert vibration-damping effect is installed on the outer periphery surface of the baffle sleeve 59 so that when vibration occurs, the damping effect will prevent the amplitude of vibration from exceeding the minimum gap.
With this type of mechanical seal, normally the collar 54, bellows 55, and retainer 56 are joined by means of welding, for example, while the seal ring 57 made of carbon or other sliding material is hermetically shrink-fitted or press-fitted in the retainer 56, and these members are preassembled as one piece at the factory, etc.
However, this mechanical seal according to the prior art has problems as described below.
When various members are installed on the seal cover 60, the collar 54, bellows 55, retainer 56, and seal ring 57 (hereinafter referred to as “seal members on the stationary side”) are installed on the equipment interior side (sealed liquid side) of the seal cover 60, while the baffle sleeve 59 which is designed as one piece having an L-shaped cross-section can be installed only from the equipment exterior side (atmosphere side) of the seal cover 60. As a result, the seal members on the stationary side, etc., cannot be preassembled with the baffle sleeve 59 and must therefore be assembled onsite. In addition, this onsite assembly requires a difficult process of wrapping around the baffle sleeve 59 the damper 61 installed between the inner periphery surface of the bellows 55 and outer periphery surface of the baffle sleeve 59, and then inserting the bellows 55.